A communications system or network may be generally defined as a collection of computers or computing systems which interact or transmit data from one computer (i.e., node) on the network to another. The functional capabilities of the nodes may range from terminals with minimal local processing capability to complex multiprocessors capable of high speed local processing. A node incorporates a set of control functions required to insure that network interfaces comply with networking standards or architectures. These control functions may be grouped into sets based on function. For example, in the Systems Network Architecture ("SNA") developed by International Business Machines Corporation ("IBM"), the assignee of the present invention, SNA defines a Physical Unit ("PU") which controls operation of real network resources such as links, and a Logical Unit ("LU") which controls logical software based entities such as applications. Other networking architectures define similar functional groupings.
The communications facilities which interconnect the nodes also may vary, ranging from high speed input/output ("I/O") channels to low speed, point-to-point telephone lines. By way of example, the media used to implement the communications facilities may include satellite links or wide band optical fibers.
Referring now to FIG. 1, a high level block diagram depicting a computer network is illustrated at 10. For purposes of illustration, the computer network 10 is shown as including a first computer which may be a sender or transmitter station 12 and a second computer which may serve as a receiver station 14. It will be understood by those skilled in the art that stations 12 and 14 may each act as either a sender, a receiver, or both a sender and a receiver, depending on whether the station is sending or receiving data. Generally, sender station 12 will include a central processing unit ("CPU") 16 and memory 18. The CPU runs the operating system 20 of sender station 12. In addition, the CPU 16 may run application programs or user operations of sender station 12. Sender station 12 interfaces with communications network 30 through communications interface 21. Communications network 30 may include satellite links or terrestrial links such as a T1 or T3 transmission link. In addition, a portion of communications network 30 may be a wired network or a wireless network. Communications interface 21 may be a modem or other means for interfacing between a station and communications network 30 in transmitting data packets.
Likewise, receiver station 14 includes a CPU 22, memory 24 and an operating system 26. CPU 22 may run application programs or user operations of receiver station 14. In addition, receiver station 14 interfaces with communications network 30 through a communications interface 27 for transmitting data packets.
The elements described above are known to those of ordinary skill in the art and will not be described further herein. It will be understood by those skilled in the art that user application programs of sender station 12 may provide user data for transmission to receiver station 14 and the received user data may be provided to the user application program of receiver station 14.
Still further, it will be understood by those skilled in the art that stations 12 and 14 may be mainframe computers such as an IBM System/390, a midrange computer such as an IBM AS-400, a server, a workstation or a personal computer. In addition, in the context of the "information superhighway" and the Internet, the sending station may be an Internet client (e.g., browser) and the receiving station 14 may be an Internet server.